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			288 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			288 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * LZO 1x decompression
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|  * Copyright (c) 2006 Reimar Doeffinger
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|  *
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|  * This file is part of Libav.
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|  *
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|  * Libav is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * Libav is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with Libav; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| #include "avutil.h"
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| #include "common.h"
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| //! Avoid e.g. MPlayers fast_memcpy, it slows things down here.
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| #undef memcpy
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| #include <string.h>
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| #include "lzo.h"
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| 
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| //! Define if we may write up to 12 bytes beyond the output buffer.
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| #define OUTBUF_PADDED 1
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| //! Define if we may read up to 8 bytes beyond the input buffer.
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| #define INBUF_PADDED 1
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| typedef struct LZOContext {
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|     const uint8_t *in, *in_end;
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|     uint8_t *out_start, *out, *out_end;
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|     int error;
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| } LZOContext;
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| 
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| /**
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|  * @brief Reads one byte from the input buffer, avoiding an overrun.
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|  * @return byte read
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|  */
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| static inline int get_byte(LZOContext *c) {
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|     if (c->in < c->in_end)
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|         return *c->in++;
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|     c->error |= AV_LZO_INPUT_DEPLETED;
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|     return 1;
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| }
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| 
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| #ifdef INBUF_PADDED
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| #define GETB(c) (*(c).in++)
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| #else
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| #define GETB(c) get_byte(&(c))
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| #endif
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| 
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| /**
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|  * @brief Decodes a length value in the coding used by lzo.
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|  * @param x previous byte value
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|  * @param mask bits used from x
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|  * @return decoded length value
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|  */
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| static inline int get_len(LZOContext *c, int x, int mask) {
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|     int cnt = x & mask;
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|     if (!cnt) {
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|         while (!(x = get_byte(c))) cnt += 255;
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|         cnt += mask + x;
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|     }
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|     return cnt;
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| }
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| 
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| //#define UNALIGNED_LOADSTORE
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| #define BUILTIN_MEMCPY
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| #ifdef UNALIGNED_LOADSTORE
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| #define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s);
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| #define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s);
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| #elif defined(BUILTIN_MEMCPY)
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| #define COPY2(d, s) memcpy(d, s, 2);
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| #define COPY4(d, s) memcpy(d, s, 4);
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| #else
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| #define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1];
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| #define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3];
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| #endif
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| 
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| /**
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|  * @brief Copies bytes from input to output buffer with checking.
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|  * @param cnt number of bytes to copy, must be >= 0
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|  */
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| static inline void copy(LZOContext *c, int cnt) {
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|     register const uint8_t *src = c->in;
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|     register uint8_t *dst = c->out;
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|     if (cnt > c->in_end - src) {
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|         cnt = FFMAX(c->in_end - src, 0);
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|         c->error |= AV_LZO_INPUT_DEPLETED;
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|     }
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|     if (cnt > c->out_end - dst) {
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|         cnt = FFMAX(c->out_end - dst, 0);
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|         c->error |= AV_LZO_OUTPUT_FULL;
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|     }
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| #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
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|     COPY4(dst, src);
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|     src += 4;
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|     dst += 4;
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|     cnt -= 4;
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|     if (cnt > 0)
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| #endif
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|         memcpy(dst, src, cnt);
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|     c->in = src + cnt;
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|     c->out = dst + cnt;
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| }
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| 
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| static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
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| 
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| /**
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|  * @brief Copies previously decoded bytes to current position.
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|  * @param back how many bytes back we start
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|  * @param cnt number of bytes to copy, must be >= 0
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|  *
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|  * cnt > back is valid, this will copy the bytes we just copied,
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|  * thus creating a repeating pattern with a period length of back.
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|  */
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| static inline void copy_backptr(LZOContext *c, int back, int cnt) {
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|     register const uint8_t *src = &c->out[-back];
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|     register uint8_t *dst = c->out;
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|     if (src < c->out_start || src > dst) {
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|         c->error |= AV_LZO_INVALID_BACKPTR;
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|         return;
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|     }
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|     if (cnt > c->out_end - dst) {
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|         cnt = FFMAX(c->out_end - dst, 0);
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|         c->error |= AV_LZO_OUTPUT_FULL;
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|     }
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|     memcpy_backptr(dst, back, cnt);
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|     c->out = dst + cnt;
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| }
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| 
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| static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
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|     const uint8_t *src = &dst[-back];
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|     if (back == 1) {
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|         memset(dst, *src, cnt);
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|     } else {
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| #ifdef OUTBUF_PADDED
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|         COPY2(dst, src);
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|         COPY2(dst + 2, src + 2);
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|         src += 4;
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|         dst += 4;
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|         cnt -= 4;
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|         if (cnt > 0) {
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|             COPY2(dst, src);
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|             COPY2(dst + 2, src + 2);
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|             COPY2(dst + 4, src + 4);
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|             COPY2(dst + 6, src + 6);
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|             src += 8;
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|             dst += 8;
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|             cnt -= 8;
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|         }
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| #endif
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|         if (cnt > 0) {
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|             int blocklen = back;
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|             while (cnt > blocklen) {
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|                 memcpy(dst, src, blocklen);
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|                 dst += blocklen;
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|                 cnt -= blocklen;
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|                 blocklen <<= 1;
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|             }
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|             memcpy(dst, src, cnt);
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|         }
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|     }
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| }
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| 
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| void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
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|     memcpy_backptr(dst, back, cnt);
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| }
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| 
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| int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
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|     int state= 0;
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|     int x;
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|     LZOContext c;
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|     if (!*outlen || !*inlen) {
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|         int res = 0;
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|         if (!*outlen)
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|             res |= AV_LZO_OUTPUT_FULL;
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|         if (!*inlen)
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|             res |= AV_LZO_INPUT_DEPLETED;
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|         return res;
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|     }
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|     c.in = in;
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|     c.in_end = (const uint8_t *)in + *inlen;
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|     c.out = c.out_start = out;
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|     c.out_end = (uint8_t *)out + * outlen;
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|     c.error = 0;
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|     x = GETB(c);
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|     if (x > 17) {
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|         copy(&c, x - 17);
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|         x = GETB(c);
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|         if (x < 16) c.error |= AV_LZO_ERROR;
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|     }
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|     if (c.in > c.in_end)
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|         c.error |= AV_LZO_INPUT_DEPLETED;
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|     while (!c.error) {
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|         int cnt, back;
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|         if (x > 15) {
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|             if (x > 63) {
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|                 cnt = (x >> 5) - 1;
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|                 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
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|             } else if (x > 31) {
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|                 cnt = get_len(&c, x, 31);
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|                 x = GETB(c);
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|                 back = (GETB(c) << 6) + (x >> 2) + 1;
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|             } else {
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|                 cnt = get_len(&c, x, 7);
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|                 back = (1 << 14) + ((x & 8) << 11);
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|                 x = GETB(c);
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|                 back += (GETB(c) << 6) + (x >> 2);
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|                 if (back == (1 << 14)) {
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|                     if (cnt != 1)
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|                         c.error |= AV_LZO_ERROR;
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|                     break;
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|                 }
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|             }
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|         } else if(!state){
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|                 cnt = get_len(&c, x, 15);
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|                 copy(&c, cnt + 3);
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|                 x = GETB(c);
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|                 if (x > 15)
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|                     continue;
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|                 cnt = 1;
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|                 back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
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|         } else {
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|                 cnt = 0;
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|                 back = (GETB(c) << 2) + (x >> 2) + 1;
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|         }
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|         copy_backptr(&c, back, cnt + 2);
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|         state=
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|         cnt = x & 3;
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|         copy(&c, cnt);
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|         x = GETB(c);
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|     }
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|     *inlen = c.in_end - c.in;
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|     if (c.in > c.in_end)
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|         *inlen = 0;
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|     *outlen = c.out_end - c.out;
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|     return c.error;
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| }
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| 
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| #ifdef TEST
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| #include <stdio.h>
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| #include <lzo/lzo1x.h>
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| #include "log.h"
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| #define MAXSZ (10*1024*1024)
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| 
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| /* Define one of these to 1 if you wish to benchmark liblzo
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|  * instead of our native implementation. */
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| #define BENCHMARK_LIBLZO_SAFE   0
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| #define BENCHMARK_LIBLZO_UNSAFE 0
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| 
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| int main(int argc, char *argv[]) {
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|     FILE *in = fopen(argv[1], "rb");
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|     uint8_t *orig = av_malloc(MAXSZ + 16);
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|     uint8_t *comp = av_malloc(2*MAXSZ + 16);
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|     uint8_t *decomp = av_malloc(MAXSZ + 16);
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|     size_t s = fread(orig, 1, MAXSZ, in);
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|     lzo_uint clen = 0;
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|     long tmp[LZO1X_MEM_COMPRESS];
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|     int inlen, outlen;
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|     int i;
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|     av_log_set_level(AV_LOG_DEBUG);
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|     lzo1x_999_compress(orig, s, comp, &clen, tmp);
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|     for (i = 0; i < 300; i++) {
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| START_TIMER
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|         inlen = clen; outlen = MAXSZ;
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| #if BENCHMARK_LIBLZO_SAFE
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|         if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
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| #elif BENCHMARK_LIBLZO_UNSAFE
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|         if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
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| #else
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|         if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
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| #endif
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|             av_log(NULL, AV_LOG_ERROR, "decompression error\n");
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| STOP_TIMER("lzod")
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|     }
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|     if (memcmp(orig, decomp, s))
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|         av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
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|     else
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|         av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
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|     return 0;
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| }
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| #endif
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